Hotel telephone system



H. V. HAYES.

HOTEL TELEPHONE SYSTEM.

Patented Dec. 25, 1888..

3 I Inuemfor.

(JJZQSSCS,

(Nq Model.)

alga/04 llnrrnn STAT S Parent wri ten HAMMOND V. HAYES, OF CAMBRIDGE, MASSACHUSETTS.

HOTEL. TELEPHONE SYSTEWL SPECIFICATION forming part of Letters Patent No. 395,137, dated December 25, 1888.

' Application filed. November 5, 1888. Serial No. 290,013 (No model.)

T0 (LZZ whom) it may concern:

Be it known that I, HAMMOND V. HAYES, residing at Cambridge, in the county of MiddleseX and State of Massachusetts, have invented certain Improvements in Hotel Telephone Systems, of which the following is a specification. 7

My invention rela as to systems of hotel.- signaling; and its object is the establislnnent of reciprocal telephonic communication between the several rooms of any building or group of buildings-such, for example, as the different departments of a factory and some central point. To accomplish this it is essential that the central station shall be able to send call-signals to each and all of the several sub-stations; that each sub-station or outlying room shall be so provided that it can send call-signals to the central station, and that when in either case the attention of the second party is attracted telephonic conversation can be carried on in either direction.

It is further in many cases desirable that the usual call-bell and annunciator-wires of a hotel shall be made available without material change, this being especially important in view of the fact that it is both expensive and frequently difficultto run ground-wires in each room for the telephone-set and for the calling by the central point of the several rooms. Most hotels are so wired for theeX- isting calling systems that another wire could only be introduced by removing a portion of the plastering or :tloor, and often, especially in the country, it is difficult to construct a number of trustworthy ground-connections. Moreover, it is not feasible to dispense with the ground-wires at each room and in lieu thereof to use the battery or return wire for telephonic purposes also, if the said batterywire be arranged as usual, for two reasons: in the first place, the battery would in that case have its circuit closed through such telephones as at any moment might be in use,

and the call-signaling would thus tend to inefficieney for want of a suificient amount of current; and, in the second place, the act of signaling the central office would cause a redistribution of the battery-current and disturb any telephonic conversation which at the moment might be going on. These considerations have led. me to devise an arrangement of telephonic and signaling circuits and apparatus which dispenses with individual ground-wires at the several rooms, which employs practically the simple ordinary arrangement of main and battery wires, and can therefore, without great expense, be substituted for or superimposed upon existing annunciator systems, while the difficulty which I have stated. has been in the way of such employment is removed by changing the position and relation of the calling battery, so that while the main battery or return wire, or a portion thereof, is in all cases utilized as one side of the talking-circuit, the battery is no longer included in such circuit, but is merely attached thereto at some point, and can therefore be used in calling over other lines in its full force.

My invention comprehends the organization in a concrete system of a number of individual electric lines radiating from a central place or point to a number of rooms or other outlying points, all of which are provided with a common return-wire, which serves also as a battery-supply wire for use in signaling from the several rooms to the central station. At each room is provided a call-receiving bell, buzzer, or vibrator, means for sending calls, a telephone, and a manual automatic switch for transferring the circuit of the direct roomline from the call-receiver to the telephone, and vice versa.

At the central station I provide a visual or other indicator to receive room calls connected with the several direct lines, and telephones and call-sending appliances connected with the central-station end of the common return-wire, which is normally open or disconnected, but which is adapted by means of a conducting-cord and plug and a spring-jack in the circuit of each room-line, or any other well-known appliance, to be united with the central-station end of any of the said individual room-lines, for the purposes of sending outgoing call-signals or of conversation, constituting, when so united, a temporary metallic circuit in which a given room and the central point are the two corresponding stations.

At any suitable point of the return or battery-supply wire I connect a branch. to earth,

IOC

in which is included a calling-battery of sufficient strength to operate the eentral-station annunciator from the most distant room. \Vhen the battery is so arranged in a branch to earth, it is evident that it can never be short circuited in the temporary metallic talking-circuit. Each individual room-line is normally grounded at the central station after passing through its spring-jack and annun- 1o ciator. At the several rooms the said indi vidual room-lin es are normally connected through the call-instrument, and by means 01"; the switch, with the common return-wire, and as the current of the battery would otherwise divide itself between the several room-lines,

the said battery being practically short-circuited through the said lines and their central-station terminal, earth, a suitable resistance sufficiently high is interposed in each individual line atsome point in the call-receiving branch, where it can be cut out when the switch is changed to the telephone. The battery is by such means kept from wasting awayunnecessarily, and is maintained at all times in good order. In sending call-signals from any room to the central station, a key is pressed which shunts the call appliance and resistance, and thus directs the battery-current practically with its entire force through 0 the annunciator of that line at thecentral.

station.

In sending calls from the central station to any room the otherwise detached plug constituting the normally open end of the com- 3 5 mon return-wire is thrust into the spring-j ack of the desired line. The said line is thereby disconnected from its normal central-station ground, and the call now being sent by the magneto-generator and signaling-key or oth- 0 erwise in the metallic circuit formed of the remainderof said line and a portion of the retu rnwire causes the call receiving appliance which with the resistance is included in such metallic circuitto give the alarm, and by turning the switch at the room end of the line and substituting the telephones for the sending apparatus at the ce'ntral-station end conversation can then be carried on; and should any other room desire to send in a call during conversation there is nothing to prevent the battery being simply branched to the return-wire, so that its current will traverse during the call-sending act that portion only of the common return-wire which intervenes between the key of the room now sending the call and the point where the battery branch touches the main return-wire.

It is sometimes necessary to send an alarm (as, for instance, in cases of. fire) from the central point or office to all the rooms at once, and for this purpose I provide a spring-jack in the main central-station ground-wire of the room-lines. \Vhen. this operation is to be performed, the plug end of the common return wire is thrust into the grouml-wire springjack, and the calling-current from the central-station magneto is thus divided between a group of lines and the alarm given at once to the several stations connected with said lines.

The drawings show in diagrama hotel system comprising a central station, anumber of rooms or outlying stations, individual lines connecting the rooms with the central station, and a common return-wire entering each room, and serving also as a battery-wire. Four rooms only are shown, these being sul'iicient to illustrate the invention. They are re spectively indicated by the letters 1), E, F, and G. At the rooms D and E the entire apparatus and circuit arrangement are shown in detail, while at the remaining rooms, I! and G, the inclosing-case and manual switch-handle only are shown, all of the parts being in practice inelosed within the said case. The rooms are connected by wires 1, 2, 5, and a with the central station, where they respectively pass through spring-jacks s, and then each through its own annunciator (I to a main ground-wire, 3]., leading to earth at M. The several annunciator drops are preferably grouped in a suitable case, A.

At the several rooms the indlvidual or direct wires pass through the room apparatus in to a permanent connection, controlled, however, as to its precise route by a suitable switch with a common return-wire. The return-wire 10 runs to each of the group of rooms branching into each room, and then continues to the central station, C; here it is ordinarily open, terminating in a conducting-cord, f, having a conneeting-plug,p,whi ch can be introduced at will into the springjacks s of any of the room-lines. The cord f connects with the main wire 10 through a key or switch, 7.2, and the office-telephones, or the room-calling devices, are included in circuit alternatively, according to the position of the said key. For this purpose I have shown two branches of the return-wire '10 between the key 7i and the point a: 011 the said wire.

From 50 one branch leads by wire 15 through the magnetc-generai or g and wire 11 to the front contact, a, of the key, and at a this branch is open at all times, except when the key is depressed. The other branch leads from the point 00 through the transmitting and receiving telephones T and 1, and by wires the key with which it is in normal contact. The transmitter 'l is shown as conn ecting with the line-wire it by means of an inductioncoil, '2', and is itself in circuit with the primary helix of said coil and with a local battery, Z); but on short lines the induction-coil may be dispensed with and a battery included with the transmitter in the main line.

At any convenient point on the return-wire w a branch, in, may be attached thereto, which branch leads through a calling-battery, B, to earth M. This earthand battery branch is really another terminal of the said returnwire, and while, as shown, it may be placed at the pointthereof which is most distant .9 and 10 to the resting or back contact 0 0t from the central station, it is also evident that this location only adopted for convenience of illustration, and that the earth branch may be placed at any other convenient'point and connected, as indicated in dotted lines at b, for, being an earth branch, it can exercise no influence over the metallic circuit when made up of a portion of the return-wire w and any ore of the room 'wires for outward calling and conversation, and is therefore available for use by other rooms. to supply current for calling the central station, even when the main return-wire is in use by some one room, and this irrespective of the special location of its connection with the said main return-wire. In the diagram, at rooms and 3, represented, respectively, by l) and E, the disposition of the circuits and apparatus in the interior of the case at is shown.

At room D the line No. l divides in to two terminal branches. This station is supposed to be in the act of communication with the central station. Consequently the switch y, which in permanent connection with the-returnwire ir, has been brought into contact with plate 1, which terminai es the tele gihone branch a of line ,4, which branch diverges from the main line at r and passes through the'telephone m.. From a pointon this lu-anch between the telephone and the point of divergence o, a sub-branch ltfLtlS to a call-key, 711-. This key has no back-contact stop, but its front contact leads by wire 2!) to the return or battery wire direct, and when the key is depressed the room-line is broughtinto connection with the return-wire, and the battery current, being thereby :t'urnished with a lowresistance route, traverses the same through the line-aim unciator at the central station and gives the call. \Vhen a line is quiescent, the switch 1 makes contact with the"lowcr plate, [1, this being the terminal of the call-aptmratus branch This branch, diverging from the main line at 1', is led through the call magnet 0 and resistance r to the said terminal. When the switch is on the lowerbranch plate, as is shown in E, the line is at rest and a call from the central point may be received.

In practice the wire 28, uniting the switch to the return-wire 11, is dispensed with, and the switch is united by a local. wire, )7, to wire 35!, which leads from the said return-wire to the key-contact. Thus, but one wire from. the return 11* to any room is necessary. In practice, also, the switch y may be provided with a retracting-spring holding it on the restingcontact 7:, and capable ot pulling it back to the said contact when removed therefrom. \Vhen so arri'tnged, it is requirex'l that the operator shall hold the latch ot' the switch down during eonversation. ()r the saidswitch may be of the well-known z'mtomatic or gravity type, in which ease it will benecessary to provide a suitable weight'to hang on the latch when not in use. In such a contingency it. will be well to add a receiving-telephone,which can serve as the operative weight, in which case the switch-connections would have to be reversed or its fulcrum placed at the extreme inner end.

I prefer to use a single magnetc-telephone, m, at each room, both as transmitter and receir'cr; but a battery transmitter may be added, in a manner well understood, if desired. The function of the resistance r in the call branch at each room is to prevent the battery from running down, as would be the case were the said resistance absent. These resistances may each be from two to three thousand ohms, according to the n umber of rooms, and assuming one hundred rooms, and at each a resistance of three thousand ohms, the joint resistance presented by the system to the battery would be thirty ohms.

A spring-jack, s, is included in the main ground-wire at the central point. To send a general alarm, the plug terminal p of the return-wire is insertedin the said jack, the magneto-machine g operated, and the key It pressed. The call is thus sent to all the rooms having lines terminating in the said ground-wire. \V here there are man y rooms a large magnetomachinc actuated by power may be p rofitabl y employed. Several groups of lines may be employed, each group having an independent call-battery, an indepemlent central-station ground, and an independent return-wire.

If desired, instead of the central-station magneto generator g, a battery and poleehanger may be employed; but the generator is preferable, as requiring no attendance.

In the figure the central station is shown as being in correspondence with room l. The switch at said room is on the telephone branch, and the central-station return-wire plug is in the jack of line 4. Thus a metallic circuit is provided for talking, as may easily be traced. The othmr rooms desiring to call the central station may do so by pressing their keys/r, and will then press down the latches of their switches and talk. The central station desiring to call any of the rooms places the plug 1) in the proper swing-jack, turns the crank of the generator, and at the sameiimeprcsses the key It.

Having now described my invention, 1 claim- 1. A hotel or factory telephone system com prising a central station, a series of rooms or sub-stations, a series of direct lines, each extending from one of the rooms to the central station and there terminating in an earthwire after passing through a spring-jack and aimunciator, a common return-line extending from the central station and lu-anching into all, of the rooms, the said line beingnormally open or disconnected at the central station, an earth branch including a callingdiattery connected, as described, with said return-line, a switch and connectionsilwrel'or at each room permanently united with said returnl'ine and 'i'iormally connecting the same with the direct line through a call-receiving instrument, and a resistance but adapted to transfer the said connection to a second branch of said direct line, including a telephone, a key or button arranged to unite the direct line with the return-line, shunting the several appliances of the former, and thereupon to direct the major part of the battery-current over the said direct line for the purpose of operating the central-station call-an]iunciator, and means for uniting the central-station end of the common return-wire to any one of the direct wires for the purpose of sending outgoing signals and to establish a talking-circuit, substantially as described.

2. In ahotel. or factory telephone system, a

thereof with the said ii'idependent line alternatively, according to the position of said 1 switch, through a call-device branch or atelephone branch, a calling-battery included in the earth-connection of the independent line, a resistance included in the telephone branch at each room to prevent short-circuiting of the battery, and a normally open keyadaptcd to short-circuit or shunt the said resistance, and thereupon to direct the battery-current over the direct line for the purpose of sending the central-station call, all in combination and substantially as described, whereby the independent line may be utilized as a -battery-supply line for all of the room-lines,

and also as a return-wire for any line in sending outgoing signals and for telephonic com- 4 5 munication.

3. The combination, in a hotel telephone system, of the group of direct lines converging from the several rooms to the central office and there provided with earth terminals, the battery-wire grounded on one side of the said battery and connected by branch wires 011 the other side of said battery with the outer end of each of the direct room-Wires,

the said battery-wire further extending to the central station, and being adapted to serve also as a return-circuit for any one of the direct lines iii-sending outgoing calls and in telephony, and suitable resistancesone for each roominterposed between each direct line and its connection with the battery line, whereby short-circuiting of the said battery is prevented, substantially as hereinbet'ore described.

4. The combination, in a hotel telephone system, of a group of direct lines adapted for signaling and for telephonic conversation converging from a number of rooms to a central station, a common ground-wire at the said central station for all of the said lines, a spring-jack included in the said ground-Wire, a common return-wire branching into all of the said rooms and normally connected by its branches with each of the said direct lines through a resistance, the said wire being normally open at its central-station end and provided with a terminal plug, whereby it may be united with the said spring-jack, so as to constitute a common metallic return for the group of direct lines, and a magneto-generator or its equivalent interposed in the said metallic circuit when so completed, whereby a general alarm may be sent from the central station to all of the said rooms, substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 29th day of October, 1888.

HAMMOND V. HAYES.

\Vitn esses:

GEo. WILLIs PIERCE, FRANK C. LocKWooD. 

